Occurrence of shallow landslides following uprooting of stumps after clear-cutting beech on heavy-snow mountain slopes
1996
Aiura, H. (Toyama-ken. Forestry and Forest Products Research Center, Kosugi (Japan)) | Kato, A. | Hasegawa, M.
Changes of uprooting or breaking moments of stump (Mr) after clear-cutting a beech (Fagus crenata Blume) stand were measured. The glide of the snow cover, and creep and glide pressure of the snow (Mp) were observed on heavy-snow mountain slopes. By comparing both, the possibility of the occurrence of shallow landslides following the uprooting of stumps was considered. The smaller was the basal diameter, and the more the number of years after cutting, the less was Mr, so it was thought to be almost explained by these two variables. Almost all of the stumps, nine years after cutting were broken around the root collars by the uprooting test. Therefore, shallow landslides following the uprooting of stumps were considered to have occurred earlier than the testing. The stability of the snow cover on a slope was different by types of vegetation and snow depths. Creep and glide pressure of the snow (Mp) almost corresponded to the displacement of the snow cover during winter. Mps were 100-300 kPa on the stable slope, about 800 kPa on the little unstable slope, and 2-5 MPa on the unstable slope. According to the results, it was suggested by a comparison of Mr and Mp that shallow landslides following the uprooting of stumps can occur on heavy-snow mountain slopes, the possibility of this was considered to increase in the case where cutting was made on the higher part of stem, and the clear-cut stand was composed of smaller trees
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